Hybrid system comprising a supercharging system and method for operation

ABSTRACT

The present invention relates to a hybrid system comprising a supercharging system for an internal combustion engine ( 1 ), the hybrid system comprising: a charging device ( 6 ) with a turbine ( 7 ) connected to a compressor ( 8 ) via a compressor shaft ( 9 ), the compressor having a high speed shaft ( 30 ); a planetary gear ( 25 ) coupled between the high speed shaft ( 30 ) and an electric motor/generator ( 20 ); a clutch ( 18   a ); and a power transmission for connecting a crank shaft ( 4 ) of the combustion engine ( 1 ) to the electric motor/generator ( 20 ) via the clutch ( 18   a ); wherein the hybrid system further comprises a system control ( 23 ) configured to operate the hybrid system in different operating modes according to a control sequence based on one, or a plurality of, input parameters representative of operational properties of the hybrid system.

FIELD OF THE INVENTION

The present invention relates to a hybrid system comprising asupercharging system for an internal combustion engine, a method foroperating a hybrid system for propulsion of a vehicle comprising aninternal combustion engine, a two-stage supercharging system for aninternal combustion engine, and a method for operating a two-stagesupercharging system. Furthermore, the present invention relates to acontrol sequence, or method, and a mode selector control sequence for ahybrid system including an exhaust gas propelled turbo superchargingsystem, a mechanical supercharging system and an electricalsupercharging/regenerating system.

The present invention further relates to supercharging and hybridsystems, and method of operation and controlling those systems, whichsystems comprise turbine(s), compressor(s), and electric system(s)comprising an electrical motor/generator being operatively connected toe.g. at least one of the compressors, and/or operatively connected by apower transmission system to a crank shaft, or any other propellingshaft, of an internal combustion engine.

BACKGROUND ART

In the field of automotive industry, much resources are and have beenallocated towards developing systems for improving the efficiency ofmotive, or propulsion, systems by e.g. reducing the overall fuelconsumption of internal combustion engines and propulsion systemscomprising internal combustion engines.

Reduced fuel consumption has e.g. been achieved by providingsupercharging systems, wherein a compressor is used for forced inductionof an internal combustion engine. In more detail, intake manifoldpressure is increased in order to decrease internal pumping andthrottling losses which, in turn, allows for decreased fuel consumption.Such a system further enables downsizing of a vehicle engine withoutsubstantially interfering with the vehicle, and vehicle engineperformance requirements. An example of a supercharging system isdescribed in the published WO 2009/014488.

Turbo charging systems are known and defined in a flow and pressurerange by the compressor and turbine characteristics in combination.However, turbo charging systems of today are in need of furtherimprovement in terms of e.g. providing further reduced energyconsumption as well as increasing the number of features of the turbocharging system.

SUMMARY OF THE INVENTION

In view of the above-mentioned and other drawbacks of the prior art, ageneral object of the present invention is to provide a more efficientsupercharging system which allows for improvements in flexibility ofrunning the supercharging system.

A further object of the present invention is to provide an improved andmore efficient hybrid drive system for propelling a vehicle comprisingan internal combustion engine, which hybrid drive system comprises asupercharging system.

These and other objects are met by the subject matters provided in theindependent claims. Preferred embodiments of the invention are presentedin the dependent claims.

According to a first aspect thereof, the present invention relates to ahybrid system comprising a supercharging system for an internalcombustion engine, the hybrid system comprising a charging device with aturbine connected to a compressor via a compressor shaft, the compressorhaving a high speed shaft; a planetary gear coupled between the highspeed shaft and an electric motor/generator; a clutch; and a powertransmission for connecting a crank shaft of the combustion engine tothe electric motor/generator via the clutch; wherein the hybrid systemfurther comprises a system control configured to operate the hybridsystem in different operating modes according to a control sequencebased on one, or a plurality of, input parameters representative ofoperational properties of the hybrid system.

The invention is based on the realization that improvements in thehybrid system can be achieved by providing a control unit enabling thehybrid system to operate in different modes. Hereby, existing hybridsystems can be made more cost efficient by integrating the superchargingsystem into the hybrid system and depending on e.g. the specific drivingscenario, a specific mode may be utilized by the hybrid system in orderto improve, for example, capacity utilization of the hybrid system andhence reduce energy consumption of the vehicle to which the hybridsystem is associated with. The modes may, for example, be to start-upthe internal combustion engine by means of the electric motor, to propelthe vehicle by means of the electric motor, which may be especiallyadvantageous in situations including frequent start-stop situations, topropel the vehicle by means of both the electric motor and the internalcombustion engine in order to reduce fuel consumption of the internalcombustion engine. As a further example, one mode may includeregeneration of electric energy to the electric motor by means of brakeenergy in a situation where the vehicle is in retardation. Other modesare of course conceivable and will be described further below inrelation to the different operating modes.

Moreover, the hybrid system according to the present invention mayutilize various embodiments of a supercharging system for realizing animproved and more efficient hybrid drive system, wherein e.g. overflowenergy from exhaust gas and/or mechanical power of the motive shaft fromthe internal combustion engine, such as braking power generated duringbraking of the vehicle, may be converted to electric power which, inturn, may be utilized and stored in order to e.g. provide motive powerto the vehicle with the electric motor. Furthermore, the electric motorof the hybrid system may be advantageously utilized in combination withthe internal combustion engine and auxiliary loads thereof. Advantageousoperational modes of various embodiments of the hybrid drive system aredescribed below.

Furthermore, the hybrid system according to the present invention mayadvantageously realize an improved supercharging system for an internalcombustion engine, which hybrid system combines and enables exhaust gasdriven, electrical motor driven and mechanically driven supercharging,and which system also allows for regeneration of energy by e.g.converting overflow energy from the exhaust gases, and/or overflowrotational energy from the internal combustion engine, or braking, toelectric energy by utilizing the electric motor as a generator, whereinthe electric energy may be stored in a battery, such as a battery packof a vehicle hybrid drive system.

For example, the supercharging system comprised in the hybrid system isan exhaust gas propelled turbo charging system, wherein the chargingdevice is an exhaust gas propelled turbo charging device comprising aturbine and a compressor. Furthermore, the charging device may form afirst stage turbo charging device for the internal combustion engine.Moreover, the system control may be incorporated in a vehicle electriccontrol unit, ECU.

According to an exemplifying embodiment, the electric motor/generator,is arranged along a common axis with the compressor shaft and the highspeed shaft, wherein a rotor member of the electric motor/generator isconnected to a first input of the planetary gear, and the high speedshaft is connected to a second input of the planetary gear, such thatthe planetary gear enables suitable transmission, or gear reduction,between the operational rotational speed of the charging device and theoperational rotational speed of the rotor member of the electricmotor/generator.

The transmission of the planetary gear may e.g. be arranged to functionbased on gear cooperation between e.g. sun, ring, and planet geardevices, or by traction cooperation between e.g. sun, ring, and planetwheel devices.

According to an exemplifying embodiment of the hybrid system, the clutchis a first clutch and wherein the hybrid system further comprises asecond clutch; wherein the planetary gear is coupled to the electricmotor/generator via the second clutch. Hence, the electricmotor/generator is connectable and disconnectable from operativeengagement with the planetary gear.

Hereby, the second clutch may connect and disconnect the electricmotor/generator from the planetary gear. It may be advantageous todisconnect the electric motor/generator from the planetary gear when,for example, the ignition is off in a petrol driven vehicle, when oilpressure in the supercharging system is low and the supercharging systemis about to build up pressure, or in a start up procedure where idlespeed is not completely stabilized. Accordingly, when starting thevehicle, it may be advantageous to disconnect the electricmotor/generator from the planetary gear. Further features and advantagesof disconnecting the second clutch is further described below.

Moreover, according to an exemplifying embodiment, the hybrid systemfurther comprises a third clutch for connecting the power transmissionto the crank shaft of the combustion engine. Hence, the powertransmission is connectable and disconnectable from operative engagementwith the crankshaft, or similar motive shaft, of the combustion engineduring operation of the hybrid system during different operationalmodes.

By providing a third clutch which may connect and disconnect the powertransmission to the crank shaft of the combustion engine, the hybridsystem may be configured to drive auxiliary loads at, for example, standstill when the combustion engine is turned off. Accordingly, theelectric motor/generator may when the combustion engine is shut offdrive e.g. air condition, infotainment systems, etc.

According to an exemplifying embodiment of the hybrid system, theplurality of operating modes comprises:

an operating mode A where the electrical motor drive auxiliary loads ofthe internal combustion engine, for example at vehicle stand-still(internal combustion engine shut-off);

an operating mode B where the electric motor starts the internalcombustion engine, from engine shut-off;

an operating mode C where the electric motor propels the vehicle, forexample by its own only or by providing motive power together with theinternal combustion engine or other vehicle propelling device/motor; andan operating mode D where brake energy from retardation of the vehicleis regenerated to electrical energy.

For example, in operating mode A, the electrical motor/generator is, asdescribed above, arranged to drive auxiliary loads by being mechanicallyconnected to an auxiliary drive belt, or the electrical motor/generatoris arranged for generating electrical power for driving electricallydriven auxiliary devices. Moreover, when the electric motor starts thecombustion engine according to the operating mode B, the above describedfirst and third clutches are engaged while the second clutch isdisengaged. The various states of the first, second and third clutchesfor the different operating modes will be described and illustratedfurther below.

According to an exemplifying embodiment of the hybrid system, theplurality of operating modes comprises:

an operating mode E where exhaust gas energy is regenerated toelectrical energy;

an operating mode F where exhaust gas energy is regenerated tomechanical energy;

an operating mode G comprising electrically driven supercharging of theinternal combustion engine; and

an operating mode H comprising mechanically driven supercharging of theinternal combustion engine;

According to an exemplifying embodiment of the hybrid system, the systemcontrol comprises a mode selecting subsystem arranged to select anoperating mode of the hybrid system based the input parameters accordingto a mode selector algorithm. Hence, a suitable operation mode of thehybrid system may be selected.

Furthermore, according to an exemplifying embodiment of the hybridsystem, the system control comprises a mode controlling subsystemarranged to control the hybrid system based on the selected operatingmode and the input parameters according to a mode control sequence.

According to an exemplifying embodiment of the hybrid system, the modecontrol sequence comprises engaging or disengaging the first (18 a),second (18 b) and third (18 c) clutches, operating the electric motor indrive mode or generate mode, based on the selected operating mode (Mode)according to the following:

Mode: 18a 18b 18c 20 A Engaged Disseng. Disseng. Drive B EngagedDisseng. Engaged Drive C Engaged N/A Engaged Drive D Engaged N/AEngaged. Generatewherein N/A denotes not applicable non-limiting features, oralternatives, which typically do not form part of the currentembodiment, or protective scope.

According to an exemplifying embodiment of the hybrid system, the modecontrol sequence comprises engaging or disengaging the first (18 a),second (18 b) and third (18 c) clutches, operating the electric motor(20) in drive mode or generate mode, opening or closing an air by-passvalve (21), and opening or closing a waste gate (22) based on theselected operating mode (Mode) according to the following:

Mode: 18a 18b 18c 20 21 22 E N/A Engaged N/A Generate N/A N/A F EngagedEngaged Engaged Generate N/A N/A G Disseng. Engaged Engaged Drive ClosedN/A H Engaged Engaged Engaged N/A Closed N/A

According to an exemplifying embodiment of the hybrid system, it furthercomprises an engine control and/or a vehicle control arranged todetermined a first vehicle parameter representative of engine rpm and/orderivatives thereof, a second vehicle parameter representative of anengine throttle position and/or derivatives thereof, and a third vehicleparameter representative of a driver pedal position and/or derivativesthereof, wherein the system control is arranged to control the hybridsystem based on the first, second and third vehicle parameters. Forexample, the vehicle parameters are sent between the system controls andsystem component sensors via a communication network, such as a CAN-busnetwork. Accordingly, the system control is coupled to the enginecontrol and the vehicle control, respectively.

According to an exemplifying embodiment of the hybrid system, it furthercomprises a battery operatively coupled to the electric motor/generator;wherein the system control is configured to:

determine a change of the driver pedal position;

close the air by-pass valves;

determine threshold state-of-charge (SOC) value of the battery; and/or

determine available electric power by comparing battery state-of-charge(SOC) with the predetermined threshold SOC-value.

According to an exemplifying embodiment of the hybrid system, if thebattery state-of-charge is above the threshold SOC-value, the systemcontrol is configured to operate the electric motor in drive mode togenerate supercharging until a reference pressure and/or mass flow (p3)is obtained.

According to an exemplifying embodiment of the hybrid system, theelectric motor/generator may comprise a sensor configured to monitoractual (real-time) turbo speed without having a turbo speed sensor. Thismay for example be achieved by calculations of electric motor/generatorsensor parameter values compensated, or multiplied, with the planetarygear ratio. Furthermore, for gears/transmissions, such as tractiondrives or variable transmission gear sets, a slip coefficient may beadded to the calculations in order to provide a more correct turbo speedmeasurement.

According to an exemplifying embodiment of the hybrid system, thecharging device comprises a variable nozzle turbine (VNT), the variablenozzle turbine being controlled by determining an error value of a bladespeed ratio, BSR(error), defined by a difference in a measured bladespeed ratio, BSR(real) and a desired blade speed ratio BSR(desired).

By providing a variable nozzle turbine (VNT), the charging efficiencyand operation of the supercharging system may be further improved duringdifferent operational conditions and modes of the hybrid system.Accordingly, the variable nozzle turbine is controlled to provide forsubstantially optimum turbine efficiency.

For example, according to an exemplifying embodiment of the hybridsystem, the charging device comprises at least one variable nozzleturbine vane.

A variable nozzle turbine, and/or a turbine with a variable nozzlevane(s), allow for the possibility of controlling the turbine whilemaintaining high operational efficiency. For example, the turbine vanesmay be rotated such that that the effective area of the vanes and, thus,the effective mass flow of, or through, the turbine for a given pressureratio may be improved. For example, the turbine operation may beimproved by adjusting the variable nozzle in relation to a blade speedratio (BSR) parameter value, which is used to describe the efficiency ofa turbine. A BSR value may e.g. be defined as

${BSR} = \frac{w_{t}r_{t}}{\sqrt{2\; c_{p}{T_{03}\left( {1 - \Pi_{t}^{\gamma\;{e^{- 1}/\gamma}\; e}} \right)}}}$

as, e.g. defined in Watson and Janota, 1982, p. 152, wherein w_(t) isturbine speed, r_(t) is turbine radius, c_(p) is turbine specific heattransfer constant, T₀₃ is turbine inlet temperature, Π_(t) is theturbine pressure ratio, which may be defined as the pressure afterdivided by the pressure before the turbine, and γ is ratio of specificheats. The definition of the BSR parameter, however, is not limited tothe above exemplifying example. Other definition of the BSR parametermay be obtained through use of ideal gas law and other developed laws(equations) of thermodynamics.

According to an exemplifying embodiment, during operation, the VNT iscontrolled by determining an error value BSR(error) which may be definedas the difference between a measured real value BSR(real), determined bymeasurement of, among other, turbo speed in the manner described abovewith the use of electric motor/generator sensor and calculation based ondesign parameters within the included planetary gear set, and a desiredvalue BSR(desired) for substantially optimum turbine efficiency,according to the following:BSR(error)=BSR(desired)−BSR(real)

wherein the error value is used for adjusting the variable nozzle(s) toimprove or obtain optimum turbine efficiency at a specific turbineoperating condition. For example, the error value is inputted into aVNT-regulator, such as a PID-regulator, and/or a closed loop regulatorsystem, which may be integrated in the system control. Suitableparameter values which are desired under differing operationalconditions and operational modes may e.g. be stored locally or remotelyon a memory device accessible by the system control. Desired parametervalues may also be determined using algorithm configured to outputsuitable parameter values based on operational parameters valuesassociated with the supercharging system, the internal combustionengine, and/or the vehicle.

For example, according to an exemplifying embodiment, the variablenozzle turbine vane is arranged to adjust turbine efficiency of thecharging device based on sensor signal from the electric motor and/or anengine control. According to an exemplifying embodiment, the hybridsystem comprises a system control including a control sequence tocontrol at least one actuator of the variable nozzle turbine vane, orvanes.

According to an example embodiment of the hybrid system, the chargingdevice is a first charging device with a first turbine connected to afirst compressor via a first compressor shaft, and wherein the hybridsystem further comprises a second turbo charging device with a secondturbine connected to a second compressor via a second compressor shaft.

Hereby, improved matching between the first and second charging devicesof the hybrid system may be realized by enabling controlling of thepressure build-up of the first charging device in relation to the secondcharging device, such that more efficient and improved charging pressureand/or mass flow of the system is maintained during switch-overoperation between the first and second charging devices. In particular,the controlling of the pressure and/or mass flow build-up of the firstcharging device is advantageously achieved by the electric motor, e.g. acombined electric motor/generator, which is operatively connected to thefirst charging device via the planetary gear and which electricmotor/generator enables measuring and actively controlling theoperation, such as the rotational speed of the turbine and compressor ofthe first charging device. Hence, undesired and inefficient dips inpressure and/or mass flow build up, and, in turn, dips in engine torquemay advantageously be avoided.

For example, the supercharging system is an exhaust gas propelled turbocharging system as described above, wherein each one of the first andsecond charging devices is an exhaust gas propelled turbo chargingdevice comprising a turbine and a compressor. Furthermore, the firstcharging device may, as also described above, form a first stage turbocharging device for the internal combustion engine and the secondcharging device may form a second stage turbo charging device for theinternal combustion engine. Vice versa, the second charging device mayform the first stage turbo charging device and the first charging devicemay form a second stage turbo charging device for the internalcombustion engine. Alternatively, or optionally, the first and secondcharging devices may be arranged in a parallel configuration.

According to an exemplifying embodiment of the hybrid system, theplurality of operating modes comprises:

an operating mode I wherein the first turbo charging device drives thesupercharging in a single-state supercharging operation at low flowrates;

an operating mode J wherein the second turbo charging device drives thesupercharging in a single-state supercharging operation at high flowrates; and

an operating mode K wherein the electrical motor/generator, controlsrotational speed of the first turbo charging device during a two-statesupercharging operation.

Furthermore, according to an exemplifying embodiment of the hybridsystem, it is arranged to operate in any one of the operating modes A toK, as described above.

According to an exemplifying embodiment of the hybrid system, the modecontrol sequence comprises engaging or disengaging the first, second andthird clutches (18 a, 18 a, 18 b), operating the electric motor in drivemode or generate mode, (20), opening or closing a first (21 a) and asecond (21 b) air by-pass valve, and opening or closing a first (22 a)and a second (22 b) waste gate based on the selected operating mode(Mode) according to the following:

Mode: 18a 18b 18c 20 21a 21b 22a 22b I N/A N/A N/A N/A Closed Open N/AOpen J N/A N/A N/A N/A Open Closed Open N/A K N/A N/A N/A N/A ClosedClosed N/A N/A

According to an exemplifying embodiment of the hybrid system, the inputparameters further comprises at least one of the following:

-   -   a first pressure and/or mass flow parameter representative of        air intake operational state (p1);    -   a second pressure and/or mass flow parameter representative of        second compressor operational state (p2);    -   a third pressure and/or mass flow parameter representative of        first compressor operational state (p3);    -   a fourth pressure and/or mass flow parameter representative of        exhaust gas operational state (p4);    -   a fifth pressure and/or mass flow parameter representative of        first turbine operational state (p5); and/or    -   a sixth pressure and/or mass flow parameter representative of        second turbine operational state (p6).

Furthermore, the electric motor/generator of the hybrid system is,according to an exemplifying embodiment, arranged to control rotationalspeed of the charging device, or charging devices. Thereby, the pressureand mass flow of the first charging device in relation to the secondcharging device and in relation to parameter values representative ofoverall hybrid system and engine operations may advantageously becontrolled by actively increasing, or decreasing, the rotational speedof the turbine and compressor of the first charging device with theelectric motor/generator.

Moreover, the supercharging system of the hybrid system may alsocomprise the features which are described below in relation to thefourth aspect of the present invention.

According to a second aspect thereof, the present invention relates to amethod for operating a hybrid system for propulsion of a vehiclecomprising an internal combustion engine;

the hybrid propulsion system comprising a supercharging system for theinternal combustion engine including an exhaust gas propelled turbosupercharging system, a mechanical supercharging system, and anelectrical supercharging/regenerating system;

wherein the exhaust gas propelled turbo supercharging system includes aturbo charging device;

the turbo charging device comprising a turbine and a compressor, thecompressor being arranged on a compressor shaft;

the exhaust gas propelled turbo supercharging system coupling theturbine to at least one exhaust outlet of the internal combustionengine, the electrical supercharging/regenerating system coupling anelectric motor/generator, to the compressor shaft via a planetgear/traction device, and the mechanical supercharging system coupling acrank shaft of the engine to the electric motor via a clutch,

the method comprising operating the hybrid system in at least one of aplurality of different operating modes.

According to an exemplifying embodiment of the method for operating ahybrid system, the clutch is a first clutch and wherein the hybridsystem further comprises a second clutch, wherein the planetary gear iscoupled to the electric motor/generator via the second clutch.

According to an exemplifying embodiment of the method for operating ahybrid system, the hybrid system further comprises: a third clutch forconnecting the power transmission to the crank shaft of the combustionengine.

According to an exemplifying embodiment of the method for operating ahybrid system for propulsion of a vehicle, the plurality of operatingmodes comprises:

an operating mode A comprising driving auxiliary loads of the internalcombustion engine with the electrical motor through mechanically drivingthe auxiliary belt, or by generator by providing electrical power toelectrical driven auxiliary loads;

an operating mode B comprising starting the internal combustion enginewith the electric motor, from engine shut-off;

an operating mode C comprising propelling the vehicle with the electricmotor, by its own or by providing motive power together with theinternal combustion engine; and/or

an operating mode D comprising regenerating electrical energy from brakeenergy by retarding the vehicle.

According to an exemplifying embodiment of the method for operating ahybrid system for propulsion of a vehicle, the plurality of operatingmodes comprises:

an operating mode E where exhaust gas energy is regenerated toelectrical energy;

an operating mode F where exhaust gas energy is regenerated tomechanical energy;

an operating mode G comprising electrically driven supercharging of theinternal combustion engine; and

an operating mode H comprising mechanically driven supercharging of theinternal combustion engine.

According to an example embodiment of the method for operating a hybridsystem for propulsion of a vehicle, the turbo charging device is a firstturbo charging device with a first turbine connected to a firstcompressor via a first compressor shaft, and wherein the hybrid systemfurther comprising a second turbo charging device comprising a secondturbine and a second compressor, the second compressor being arranged ona second compressor shaft.

According to an example embodiment of the method for operating a hybridsystem for propulsion of a vehicle, the plurality of operating modescomprises:

an operating mode I comprising driving the first turbo charging devicein a single-state supercharging operation at low flow rates;

an operating mode J comprising driving the second turbo charging devicein a single-state supercharging operation at high flow rates; and

an operating mode K comprising controlling, with the electricalmotor/generator, the rotational speed of the first turbo charging deviceduring a two-state supercharging operation.

Furthermore, the method is advantageous for controlling systemscomprising separate supercharging systems, since it may reduce the needfor several methods/control sequences and several differentsupercharging systems.

Effects and features of this second aspect are largely analogous tothose described above in relation to the first aspect of the presentinvention.

According to a third aspect thereof, the present invention relates to acontrol sequence for a hybrid system including an exhaust gas propelledturbo supercharging system, a mechanical supercharging system, and anelectrical supercharging/regenerating system, a charging device and anelectric motor/generator, operatively connected to the charging device,wherein the hybrid system is arranged to operate in different operatingmodes.

For example, according to an exemplifying embodiment of the controlsequence for a hybrid system, it is configured for engaging ordisengaging a first (18 a), second (18 b) and third (18 c) clutches,operating an electric motor (20) in drive mode or generate mode, basedon a selected operating mode (Mode) according to the following:

Mode: 18a 18b 18c 20 A Engaged Disseng. Disseng. Drive B EngagedDisseng. Engaged Drive C Engaged N/A Engaged Drive D Engaged N/A EngagedGenerate

For example, according to an exemplifying embodiment of the controlsequence for a hybrid system, the control sequence is configured forengaging or disengaging a first (18 a), a second (18 b) and a third (18c) clutch, operating an electric motor (20) in drive mode or generatemode, opening or closing an air by-pass valve (21), and opening orclosing a waste gate (22) of the hybrid system based on a selectedoperating mode (Mode) according to the following:

Mode: 18a 18b 18c 20 21 22 E N/A Engaged N/A Generate N/A N/A F EngagedEngaged Engaged Generate N/A N/A G Disseng. Engaged Engaged Drive ClosedN/A H Engaged Engaged Engaged N/A Closed N/A

According to an exemplifying embodiment of the control sequence for ahybrid system, the charging device is a first turbo charging device witha first turbine connected to a first compressor via a first compressorshaft, and wherein the hybrid system further comprises a second turbocharging device comprising a second turbine and a second compressor, thesecond compressor being arranged on a second compressor shaft.

For example, according to an exemplifying embodiment of the controlsequence for a hybrid system, it is configured for engaging ordisengaging a first (18 a), second (18 b) and third (18 c) clutches,operating an electric motor (20) in drive mode or generate mode, openingor closing a first (21 a) and a second (21 b) air by-pass valve, andopening or closing a first (22 a) and a second (22 b) waste gate of thehybrid system based on a selected operating mode (Mode) according to thefollowing:

Mode: 18a 18b 18c 20 21a 21b 22a 22b I N/A N/A N/A N/A Closed Open N/AOpen J N/A N/A N/A N/A Open Closed Open N/A K N/A N/A N/A N/A ClosedClosed N/A N/A

Effects and features of this third aspect are largely analogous to thosedescribed above in relation to the first and second aspects of thepresent invention.

According to a fourth aspect thereof, the present invention relates to asupercharging system for an internal combustion engine, comprising: afirst charging device with a first turbine connected to a firstcompressor via a first compressor shaft, the compressor having a highspeed shaft; a planetary gear coupled between the high speed shaft andan electric motor/generator; a first clutch; and a power transmissionfor connecting a crank shaft of the combustion engine to the electricmotor/generator via the first clutch; the supercharging system furthercomprising a second charging device with a second turbine connected to asecond compressor via a second compressor shaft.

According to an exemplifying embodiment, the supercharging systemfurther comprises a system control arranged to control a parameterrepresentative of pressure and/or mass flow of the first charging devicein relation to the second charging device during matching between thefirst and the second charging devices.

For example, according to an exemplifying embodiment of thesupercharging system, the system control may be arranged to control thepressure and/or mass flow operating point of the first charging devicein relation to the second charging device during matching between thefirst and to the second charging device. For example, the electric motoris controlled, or arranged, to maintain boost pressure of compressed airto be delivered into the internal combustion engine during switch-overconditions. Furthermore, the electric motor may be controlled, orarranged, to match the operating point of the first charging device withthe operating point of the second charging device during switch-over,when the second charging device is operating in a free-floatingconfiguration. Hence, it is e.g. possible to momentarily assist thefirst charging device by electrical drive if required.

According to an exemplifying embodiment of the supercharging system, thesupercharging system comprises a system control arranged to control therotational speed of the first charging device according to a referencespeed value based on at least one parameter representative of anoperational property of the supercharging system provided to the systemcontrol. For example, the system control may also be arranged to controlthe supercharging system, and the first charging device of thesupercharging system, based on operational parameters representative ofe.g. engine rpm, engine throttle position and/or derivatives thereof,and/or a driver pedal position and/or derivatives thereof. For example,the position of the driver pedal, and/or derivatives thereof, mayinitiate controlling, by the system control, of the rotational speed ofthe electric motor and the compressor of the first charging device.

Moreover, according to an exemplifying embodiment, the electricmotor/generator comprises a sensor arranged to generate a motor speedparameter value representative of the rotational speed of the electricmotor/generator, wherein the system control is arranged to control therotational speed of the first charging device, i.e. the turbo speed,based on the motor speed parameter according to a control sequence. Forexample, the sensor may be arranged as a separate unit and/or be atleast partly formed by the electric motor/generator itself.

The supercharging system may further comprises waste gates for enablingimproved and more efficient operation of the supercharging system bycontrolling and adjusting the mass flow through the turbines of thesystem. For example, according to an exemplifying embodiment of thesupercharging system, it comprises an operable first waste gate coupledbetween an inlet side of the first turbine and an inlet side of thesecond turbine. According to a further exemplifying embodiment of thesupercharging system, it further comprises a second waste gate coupledbetween the inlet side of the second turbine and an exhaust gas outlet.

Moreover, according to exemplifying embodiments of the superchargingsystem, it further comprises a first air by-pass valve and/or a secondair by-pass valve, wherein the by-pass valves are arranged for at leastpartly bypassing the first and second compressor of the first and secondcharging devices, respectively, during operation of the superchargingsystem.

According to an exemplifying embodiment of the supercharging system, thefirst charging device is a variable nozzle turbine, and thesupercharging system further comprises a system control operativelyconnected to determine and control the state of the variable nozzleturbine, the first, second and third clutches, the electricmotor/generator, the first and second air by-pass valves, and the firstand second first waste gates. Hence, the system control is arranged toretrieve, or receive signals from the different components of thesupercharging system and determine their operational state, and tofurther control the supercharging system by controlling the componentsof the system. For example, the system control communicates over acommunication network connected to the supercharging system. Thecommunication network may e.g. be a CAN-bus network, or any othersuitable communication network. The system control may furthercommunicate with and/or retrieve information from surrounding controlunits, such as an engine control, a vehicle control, etc. The describedsupercharging system may be incorporated in the above described hybridsystem. However, the supercharging system is not limited to beincorporated in the above hybrid system and may hence also beincorporated in other systems as well.

Further effects and features of this fourth aspect are largely analogousto those described above in relation to the first, second and thirdaspects of the present invention.

According to a fifth aspect thereof, the present invention relates to amethod for operating a supercharging system for the internal combustionengine including an exhaust gas propelled turbo supercharging system, amechanical supercharging system, and an electricalsupercharging/regenerating system;

wherein the exhaust gas propelled turbo supercharging system includes afirst and second turbo charging device;

the first turbo charging device comprising a first turbine and a firstcompressor, the first compressor being arranged on a first compressorshaft;

the second turbo charging device comprising a second turbine and asecond compressor, the second compressor being arranged on a secondcompressor shaft;

the exhaust gas propelled turbo supercharging system coupling the firstand second turbines to at least one exhaust outlet of the internalcombustion engine, the electrical supercharging/regenerating systemcoupling an electric motor/generator, to the first and/or secondcompressor shaft via a planet gear, and the mechanical superchargingsystem coupling a crank shaft of the engine to the electric motor via afirst clutch,

the method comprising: sensing and/or controlling rotational speed ofthe first compressor of the first turbo charging device with theelectric motor during matching between the first and to the second turbocharging devices.

Hence, the method provides improved and more efficient operation of thesupercharging system, wherein the pressure dips of the superchargingsystem and torque dips associated with the internal combustion engineduring matching between a first and second charging device may bereduced, or avoided. In more detail, the method and system allow fordirect control of the first charging device since it is connected to anelectric motor which may be utilized for measuring the operational stateof the turbine and compressor of the first charging device, and tocontrol the operation, such as the rotational speed, of the compressorof the first charging device. Furthermore, the method is advantageous insimilar manners as described above in relation to the superchargingsystem and the hybrid drive system.

According to an exemplifying embodiment of the method for operating asupercharging system, it further comprises driving the first compressorof the first turbo charging device with the electric motor until areference pressure and/or mass flow (p3) of the supercharging system isobtained. For example, the reference pressure and/or mass flow value isrepresentative of the operating pressure of mass flow provided by thesupercharging system to the intake manifold, or e.g. an intercoolerdevice, associated with the internal combustion engine.

Further effects and features of this fifth aspect are largely analogousto those described above in relation to the first, second, third andfourth aspects of the present invention.

According to a sixth aspect thereof, the present invention relates to amode selector control sequence for a hybrid system including an exhaustgas propelled turbo supercharging system, a mechanical superchargingsystem, and an electrical supercharging/regenerating system, a firstcharging devices including a first turbine and a first compressor, asecond charging devices including a second turbine and a secondcompressor, and an electric motor/generator, operatively connected tothe first charging device, wherein the hybrid system is arranged tooperate in different operating modes, the mode selector algorithm beingconfigured to select an operating mode for the hybrid system based oninput parameter values representative of respective operating states ofa first, second and third clutches, a operating state of an electricmotor, respective operating states of a first and second air by-passvalves, and operating states of a first and second waste gates, of thehybrid system.

According to an exemplifying embodiment of the mode selector controlsequence, the input parameters further comprises at least one of thefollowing:

-   -   a first pressure and/or mass flow parameter representative of        air intake operational state (p1);    -   a second pressure and/or mass flow parameter representative of        second compressor operational state (p2);    -   a third pressure and/or mass flow parameter representative of        first compressor operational state (p3);    -   a fourth pressure and/or mass flow parameter representative of        exhaust gas operational state (p4);    -   a fifth pressure and/or mass flow parameter representative of        first turbine operational state (p5); and/or    -   a sixth pressure and/or mass flow parameter representative of        second turbine operational state (p6).

Effects and features of this sixth aspect are largely analogous to thosedescribed above in relation to the first, second, third, fourth andfifth aspects of the present invention.

According to a seventh aspect thereof, the present invention relates toa supercharging system for an internal combustion engine, comprising: afirst charging device with a first turbine connected to a firstcompressor via a first compressor shaft, the compressor having a highspeed shaft; a planetary gear coupled between the high speed shaft andan electric motor/generator; a first clutch; and a power transmissionfor connecting a crank shaft of the combustion engine to the electricmotor/generator, via the first clutch; wherein the supercharging systemfurther comprises a second clutch; wherein the planetary gear is coupledto the electric motor/generator, via the second clutch.

Hereby, the planetary gear and the electric motor/generator may beconnected and disconnected from each other. This enables a desirableconnection between the electric motor/generator and the planetary geartraction device in modes of operation such as, for example, when theinternal combustion engine is running and simultaneously regeneratesenergy to the electric generator. As also described above, the electricmotor/generator may be disconnected from the planetary gear when, forexample, the combustion engine is turned off, when idle speed isnon-stable or when oil pressure is low and is about to be built up inthe supercharging system.

Effects and features of this seventh aspect are largely analogous tothose described above in relation to the first, second, third, fourth,fifth and sixth aspects of the present invention.

Generally, other objectives, features, and advantages of the presentinvention that will appear from the following detailed disclosure, fromthe attached dependent claims as well as from the drawings are equallypossible within the scope of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings, wherein:

FIG. 1a is a schematic view of a supercharging system and a hybrid drivesystem according to an embodiment of the present invention.

FIG. 1b is a schematic view of a supercharging system and a hybrid drivesystem according to a further embodiment of the present invention.

FIG. 2 is a schematic block diagram which illustrates embodiments of thesystem control of the supercharging device, and which schematicallyillustrates embodiments of the method for operating a superchargingsystem according to the present invention.

FIG. 3 is a schematic diagram of operating modes A-F of an embodiment ofthe supercharging system according to the present invention duringgeneric vehicle driving conditions.

It should be understood that the drawings are only schematic and nottrue to scale and, as is readily appreciated by a person skilled in theart, dimensions other than those illustrated in the drawings are equallypossible within the scope of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the drawings, similar, or equal elements are referred to by equalreference numerals.

Reference is now drawn to the figures, and to FIG. 1a in particulardepicting an internal combustion engine 1 having an air intake manifold2 with four air intake pipes, depicting that the engine has fourcylinders. However, the number of cylinders can be higher as well aslower. The internal combustion engine 1 further has an exhaust gasmanifold 3, having four exhaust gas pipes for the four cylinders of theengine.

Attached to the engine block is a charging device 6 comprising a turbocharging device comprising a turbine 7 and a compressor 8 arranged on acommon shaft 9 in such a way that when the turbine rotates thecompressor rotates simultaneously. The compressor 8 is connected to ahigh-speed shaft 30 projecting in the opposite direction to the commonturbine/compressor shaft 9. The turbine is driven by the exhaust gasesfrom the exhaust gas manifold 3, and an impeller (not shown) of theco-rotating compressor 8 is compressing ambient air which is sucked invia an air filter 10. The compressed air is lead through a duct 11 viaan intercooler 12 and a throttle 13 into the internal combustion engine1 through the air intake manifold 2, whereas the exhaust gases afterhaving passed the turbine are evacuated via an exhaust gas conduit 14with a catalyzer 15. The throttle 13 may for example be an electricallycontrolled throttle.

The engine 1 has a crankshaft 4 which protrudes outside the engine andis equipped with a pulley 5. The pulley 5 is rotating with thecrankshaft 4 of the engine and transfers via a belt drive 16 rotation toa shaft 17, which via a one way clutch 18 a is coupled to an electricmotor/generator 20, which in turn is coupled through a low-speed shaft31 to a ring gear wheel (not shown) of a planetary gear 25 with planetgear wheels (not shown) and a sun gear wheel (not shown) connected tothe high-speed shaft 30. In this manner the rotation of the crank shaft4 can be transferred to the shaft 9, which is the common shaft for theturbine 7 and the compressor 8, in situations where the turbine has notreached its working area. The belt drive described is not limited to bea belt drive, any type of appropriate transmission units can be used.The clutch mentioned can be mechanical one way clutch of any appropriatetype, although electric clutches, viscous couplings and the like arealso possible.

Furthermore, the catalyzer may be preheated up to normal operatingtemperature by driving the electric motor 20 which hence affecting thecharging device 6 which heats the catalyzer 15. Hereby, the catalyzermay be heated to its operating temperature, or approximately to itsoperating temperature, before the internal combustion engine is turnedon, thereby reducing pollution as well as fuel consumption.

The engine also incorporates a compressor bypass valve 21 and a wastegate 22. The compressor bypass valve 21 is controlled by way of a systemcontrol 23, which based on different engine behaviour parameters, willoperate for maintaining the rotational speed of the turbine so high aspossible in order to avoid dangerous pressure increase at the exhaustside. The system control 23 is further operatively connected to anengine control 28, and a vehicle control 29.

Furthermore, as described above, the planetary gear 25 comprises e.g. aring wheel, two or a plurality of planet wheels, and a sun wheel. Inmore detail, the high speed shaft 30 of the charging device 6, whichhigh speed shaft 30 is connected to and extends from the compressorshaft 9, is connected to the sun wheel, on a high speed side of theplanetary gear 25. On the other side of the planetary gear 25, on a lowspeed side, a low speed shaft 31 is connected to and provided betweenthe ring wheel and a second clutch 18 b. The second clutch 18 b connectsthe low speed shaft with the electrical motor/generator 20, or, in moredetail, a rotor member of the electric motor/generator 20. The secondclutch 18 b may be arranged to disconnect the electric motor/generator20 from the planetary gear 25 when the combustion engine is turned off.Hereby, the electric motor can drive auxiliary loads of the vehicle.Also, the second clutch 18 b may be disengaged when oil pressure is lowand is about to be built up in the supercharging system, or when idlespeed is unstable. Accordingly, when the oil pressure has reach adesired pressure level and/or when the idle speed is stable, the secondclutch 18 b connects the electric motor/generator 20 with the planetarygear.

As illustrated, the low speed shaft 31 on the low speed side of theplanetary gear 25 coincides with the axis of the electricalmotor/generator 20. Hence, the low speed shaft 31 is also coupled to thecrankshaft 4 of the engine 1 via clutches 18 a, 18 b, and 18 c.

However, the electrical motor/generator 20 may be arranged separatedfrom and connected to the low speed shaft 31 via a suitabletransmission, such as a belt drive. Furthermore, the electricalmotor/generator 20 may be operatively connected to the common axis ofthe high speed shaft 30 and low speed shaft 31 on the high speed side ofthe planetary gear 25. For example, a high speed electricalmotor/generator may be used and operatively connected to the high speedshaft 30, optionally via a clutch.

As illustrated in FIG. 1a , the system 1 comprises power transmission16, such as a belt drive, which operatively connects the common axis ofthe electric motor/generator 20 and low speed shaft 31, via a firstclutch 18 a and third clutch 18 c, to the crankshaft 4 of the engine 1,such that rotational power may be transferred between the crankshaft andthe common axis of the electric motor/generator 20, the low speed shaft31, planetary gear 25, and the high speed shaft 30, depending on theconfiguration of the first 18 a and second 18 b clutches.

For example, the high speed shaft 30 may be used for providingrotational power from the electric motor/generator to the chargingdevice 6 for enabling e.g. electrically powered charging of the internalcombustion engine, referred to as e-boost, or for enabling mechanicallypowered turbo charging of the electrical engine by using mechanicalrotational power from the internal combustion engine. The high speedshaft 30 may also be used for obtaining, or extracting, the rotationalpower generated in the charging device, typically in the turbine, and toconvert this produced rotational power into electric energy be means ofthe electric motor which is configured to operate as a generator andwhich is connected to the drive shaft, or to convert the rotationalpower into mechanical power be means of the power transmission 16.

As further illustrated, the first charging device includes a variablenozzle turbine (VNT) which comprises variable vanes 19 which may beadjusted by the system control 23 in order adapted the turbine tocurrent exhaust gas flow condition and the operational mode of thesupercharging system. The system control 23 is connected to and arrangedto control the first 18 a, second 18 b and third 18 c clutches, and theengine's throttle 13 according to the different operating modes of thehybrid system 100, such as operating modes A-H described above.

Turning to FIG. 1b , there is depicted a schematic view of asupercharging system 100 and/or hybrid drive system 100 according to anembodiment of the present invention, is illustrated. The superchargingsystem 100 comprises an internal combustion engine 1, in the followingalso referred to as the engine 1, comprising an intake manifold 2 forallowing compressed air to enter into the engine 1. The engine 1 furthercomprises a exhaust manifold 3 for exhaust gases leaving the engine 1,which exhaust gases are used for driving turbines 7 a and 7 b of a first6 a and a second 6 b charging device, respectively. The engine furthercomprises a crankshaft which is arranged to provide rotational power forpropelling a vehicle, such as a car, truck, lift-truck, constructionvehicle, buss, ship, boat, aircraft, or other vehicles or crafts, via apropulsion drive line. A crankshaft pulley 5 is connected to thecrankshaft 4, which pulley 5 forms part of a belt drive powertransmission between the crankshaft 4 and an electric motor/generator20. However, the power transmission between engine and electrical motoris not limited to a belt drive transmission.

As illustrated, the system 100 comprises a first charging device 6 acomprising a first turbine 7 a being arranged downstream of, in relationto the exhaust gas flow, and connected to the exhaust gas manifold 3,and a first compressor 8 a for generating compressed air to the suppliedto the engine 1. The first turbine 7 a is connected via a firstcompressor shaft 9 a to the first compressor 8 a, such that rotationalpower provided by the exhaust gases from the engine to the first turbine7 a may be transferred to the first compressor 8 a. The system 100further comprises a second charging device 6 b comprising a secondturbine 7 b being arranged downstream of, in relation to the exhaust gasflow, and connected to the outlet side of the first turbine 7 a, and asecond compressor 8 b for generating compressed air to the supplied tothe engine 1. The second turbine 7 b is connected via a secondcompressor shaft 9 b to the second compressor 8 b, such that rotationalpower provided by the exhaust gases from the engine to the secondturbine 7 b may be transferred to the second compressor 8 b. Hence, thesecond charging device 6 b is arranged sequentially after the firstcharging device 6 a, in relation to the exhaust gas flow. However, theinvention is not limited to this configuration, and the second chargingdevice 6 b may be arranged before, or in a parallel configuration with,the first charging device 6 a, in relation to the exhaust gas flow.

On an exhaust gas system side of the system 100, it further comprises afirst 22 a and second 22 b waste gate which enables bypassing of theexhaust gases in relation to the first 7 a and second 7 b turbines,respectively, either independently or in combination. For example, ifpartially opened, the waste gates 22 a, 22 b enable bypassing of atleast a portion of the exhaust gas directly to an exhaust system outlet14, optionally via an exhaust gas catalyzer 15.

On a compressor system side of the system 100, air from an air inlet andair inlet filer 10 is compressed and provided to the engine e.g. viaengine air inlet ducts 11, intercooler 12 and/or throttle 13. The air isat least partly compressed by the first 8 a and second 8 b compressors,independently or in combination, depending on the configuration of afirst 21 a and a second 21 b air by-pass valves.

By adjusting the air by-pass vales 21 a, 21 b and the waste gates 22 a,22 b, the relative operation of the first and second charging device 6 aand 6 b may be adjusted in relation to each other, such that only one isoperational in a single stage operational mode, or both are operationalin an combined operational mode wherein the operational ratio betweenthe first and second charging devices may be suitably adjusted.

As further illustrated, the first charging device 6 a is arranged alonga common axis with, and operatively connected to, via a planetary gear25, to the electrical motor/generator 20 such that the electricalmotor/generator 20 may, according to various embodiments, operate bothas an electric motor and/or as an electrical generator.

As schematically illustrated, the planetary gear 25 comprises e.g. aring wheel 24, two or a plurality of planet wheels 26, and a sun wheel27. In more detail, a high speed shaft 30 of the first charging device 6a, which high speed shaft 30 is connected to and extends from the firstcompressor shaft 9 a, is connected to the sun wheel 27, on a high speedside of the planetary gear 25. On the other side of the planetary gear25, on a low speed side, a low speed shaft 31 is connected to andprovided between the ring wheel 24 and a second clutch 18 b. The secondclutch 18 b connected the low speed shaft with the electricalmotor/generator 20, or, in more detail, a rotor member of the electricmotor/generator 20.

As illustrated, the low speed shaft 31 on the low speed side of theplanetary gear 25 coincides with the axis of the electricalmotor/generator 20. Hence, the low speed shaft 31 is also coupled to thecrankshaft 4 of the engine 1 via clutches 18 a, 18 b, and 18 c.

However, the electrical motor/generator 20 may be arranged separatedfrom and connected to the low speed shaft 31 via a suitabletransmission, such as a belt drive. Furthermore, the electricalmotor/generator 20 may be operatively connected to the common axis ofthe high speed shaft 30 and low speed shaft 31 on the high speed side ofthe planetary gear 25. For example, a high speed electricalmotor/generator may be used and operatively connected to the high speedshaft 30, optionally via a clutch.

As illustrated in FIG. 1b , the system 1 comprises power transmission16, such as a belt drive, which operatively connects the common axis ofthe electric motor/generator 20 and low speed shaft 31, via a firstclutch 18 a and third clutch 18 c, to the crankshaft 4 of the engine 1,such that rotational power may be transferred between the crankshaft andthe common axis of the electric motor/generator 20, the low speed shaft31, planetary gear 25, and the high speed shaft 30, depending on theconfiguration of the clutches 18 a and 18 b.

For example, the high speed shaft 30 may be used for providingrotational power from the electric motor/generator to the first chargingdevice for enabling e.g. electrically powered charging of the internalcombustion engine, referred to as e-boost, or for enabling mechanicallypowered turbo charging of the engine by using mechanical rotationalpower from the internal engine. The high speed shaft 30 may also be usedfor obtaining, or extracting, the rotational power generated in thecharging device, typically in the turbine, and to convert this producedrotational power into electric energy be means of the electric motorwhich is configured to operate as a generator and which is connected tothe drive shaft, or to convert the rotational power into mechanicalpower be means of the power transmission 16.

As further illustrated, the first charging device includes a variablenozzle turbine (VNT) which comprises variable vanes 19 which may beadjusted by the system control 23 in order adapted the turbine tocurrent exhaust gas flow condition and the operational mode of thesupercharging system. The system control 23 is further operativelyconnected to an engine control 28, and a vehicle control 29. The systemcontrol 23 is connected to and arranged to control the first 18 a,second 18 b and third 18 c clutches, the first and second air by-passvales 21 a, 21 b and the waste gates 22 a, 22 b, and the engine'sthrottle 13 according to the different operating modes of the hybridsystem 100, such as operating modes A-K described above.

The system control 23 is further operatively connected to sensorsarranged to output observation parameter values representative ofair/exhaust gas pressure and/or mass flow at a plurality of observationspoint, or regions, such as the illustrated intake air point p1, secondcompressor point p2, first compressor point p3, exhaust gas point p4,first turbine point p5, and second turbine point p6.

In FIG. 2, a block diagram which illustrates embodiments of the systemcontrol 200 of the hybrid system, and which schematically illustratesembodiments of method steps for operating a hybrid system according tothe present invention, is schematically represented.

As illustrated, the system control 200 comprises a mode selectingsubsystem 201 arranged to select an operating mode from a set 202 ofoperating modes A-K based on a set 204 of input/output parameter valuesfrom sensors and actuators of the hybrid system. The system controlfurther comprises a mode controlling subsystem 203 arranged to controlthe hybrid system, based on the selected operating mode and the set 204of input/output parameters values from sensors and actuators of thehybrid system. Furthermore, the mode controlling subsystem 203 providesa feedback control signal 206 to the mode selecting subsystem 201 whichenables suitable shifting of operating modes based on the currentlyactive operating mode.

In FIG. 3, a diagram of exemplifying operating modes of the hybridsystem according to the present invention during a generic vehicledriving sequence, is schematically illustrated. In more detail, thediagram illustrates a driving sequence comprising different operatingmodes A (indicated 1), B (indicated by 2), C (indicated by 3), D(indicated by 4), E (indicated by 5), and F (indicated by 6) occurringduring a time period represented by the x-axis, wherein the y-axisrepresents vehicle speed.

The “A-level” is representative of a specific vehicle speed required inorder to regenerate exhaust gas energy into useful power within thehybrid system during positive transient conditions, i.e. when thevehicle is accelerating. The “B-level” is representative of anexemplifying specific vehicle speed which may be required in order toregenerate exhaust gas energy into useful power within the hybrid systemduring steady-state conditions, i.e. when the vehicle is moving withconstant speed.

For example, the specific speed requirements for passing these “levels”varies depending on vehicle and combustion engine parameters as well assurrounding conditions and is designing parameters when adapting thesystem to a specific application.

It should be noted that the invention has mainly been described abovewith reference to a few embodiments. However, as is readily appreciatedby a person skilled in the art, other embodiments than the onesdisclosed above are equally possible within the scope of the invention,as defined by the appended patent claims.

It is further noted that, in the claims, the word “comprising” does notexclude other elements or steps, and the indefinite article “a” or “an”does not exclude a plurality. A single apparatus or other unit mayfulfill the functions of several items recited in the claims. The merefact that certain features or steps are recited in mutually differentdependent claims does not indicate that a combination of these featuresor method steps cannot be used to advantage.

I claim:
 1. A hybrid system of an internal combustion engine (1)comprising: at least one charging device (6) with a turbine (7)connected to a compressor (8) via a compressor shaft (9), the compressorhaving a high speed shaft (30); a planetary gear (25) coupled betweenthe high speed shaft (30) and an electric motor/generator (20); at leastone clutch; wherein the at least one clutch includes a first clutch (18a), a second clutch (18 b), and a third clutch (18 c); a powertransmission connecting a crank shaft (4) of the combustion engine (1)to the electric motor/generator, (20) via the first clutch (18 a); atleast one of an engine controller (28) and a vehicle controller (29)arranged to determine at least one of input parameters including anengine speed (rpm), an engine throttle position, and a driver pedalposition, and an electronic control system (23) configured to operatethe hybrid system in a plurality of different operating modes accordingto a control sequence based on the at least one of said input parametersincluding the engine speed (rpm), the engine throttle position, and thedriver pedal position; wherein the plurality of said different operatingmodes comprising: an operating mode A where the electric motor drivesauxiliary loads of the internal combustion engine (1); an operating modeB where the electric motor starts, or stops, the internal combustionengine (1); an operating mode C where the electric motor propels thevehicle; and an operating mode D where brake energy from retardation ofthe vehicle is regenerated to electrical energy.
 2. The hybrid systemaccording to claim 1, wherein the planetary gear (25) is coupled to theelectric motor/generator (20) via the second clutch (18 b).
 3. Thehybrid system according to claim 1, wherein the third clutch (18 c)connects the power transmission to the crank shaft (4) of the combustionengine (1).
 4. The hybrid system according to claim 1, wherein theplurality of said different operating modes further comprises: anoperating mode E where exhaust gas energy is regenerated to electricalenergy; an operating mode F where exhaust gas energy regenerated tomechanical energy; an operating mode G comprising electrically drivensupercharging of the internal combustion engine (1); and an operatingmode H comprising mechanically driven supercharging of the internalcombustion engine (1).
 5. The hybrid system according to claim 1,wherein the electronic control system comprises a mode selectingsubsystem arranged to select one of the plurality of said differentoperating modes of the hybrid system based the input parametersaccording to a mode selector algorithm.
 6. The hybrid system accordingto claim 1, wherein the electronic control system comprises a modecontrolling subsystem arranged to control the hybrid system based on theselected operating mode and the input parameters according to a modecontrol sequence.
 7. The hybrid system according to claim 6, furthercomprising: the third clutch (18 c) for connecting the powertransmission to the crank shaft (4) of the combustion engine (1);wherein the mode control sequence comprises: engaging or disengaging thefirst clutch, second clutch and third clutch (18 a, 18 b, 18 c), andoperating the electric motor (20) in drive mode or generate mode basedon the selected operating mode (Mode) according to the following: Mode:18a 18b 18c 20 A Engaged Disseng. Disseng. Drive B Engaged Disseng.Engaged Drive C Engaged N/A Engaged Drive D Engaged N/A Engaged.Generate.


8. The hybrid system according to claim 6, further comprising: the thirdclutch (18 c) for connecting the power transmission to the crank shaft(4) of the combustion engine (1); wherein the mode control sequencecomprises engaging or disengaging the first clutch, second clutch andthird clutch (18 a, 18 b, 18 c), operating the electric motor, openingor closing an air by-pass valve (21), and opening or closing a wastegate (22) based on the selected operating mode (Mode) according to thefollowing: Mode: 18a 18b 18c 20 21 22 E N/A Engaged N/A Generate N/A N/AF Engaged Engaged Engaged Generate N/A N/A G Disseng. Engaged EngagedDrive Closed N/A H Engaged Engaged Engaged N/A Closed N/A.


9. The hybrid system according to claim 6, further comprising at leastone of the engine controller (28) and the vehicle controller (29)arranged to determine a first vehicle parameter representative of theengine rpm, a second vehicle parameter representative of at least one ofthe engine throttle position and derivatives thereof, and a thirdvehicle parameter representative of at least one of the driver pedalposition and derivatives thereof, wherein the electronic control system(23) is arranged to control the hybrid system based on the first, secondand third vehicle parameters.
 10. The hybrid system according to claim6, further comprising a battery operatively coupled to the electricmotor/generator; wherein the electronic control system (23) isconfigured to execute at least one of: determining a change of thedriver pedal position; closing the air by-pass valve (21); determiningthreshold state-of-charge (SOC) value of the battery; and determiningavailable electric power by comparing battery state-of-charge (SOC) withthe predetermined threshold SOC-value.
 11. The hybrid system accordingto claim 10, wherein, if battery state-of-charge is above the thresholdSOC-value, the electronic control system (23) is configured to operatethe electric motor in drive mode to generate supercharging until atleast one of a reference pressure and a mass flow (p3) is obtained. 12.The hybrid system according to claim 1, wherein the charging deviceincludes a first turbo charging device (6 a) with a first turbine (7 a)connected to a first compressor via a first compressor shaft (9 a), anda second turbo charging device (6 b) with a second turbine (7 b)connected to a second compressor via a second compressor shaft (9 b).13. The hybrid system according to claim 12, wherein the plurality ofsaid operating modes comprises: an operating mode I wherein the firstturbo charging device drives the supercharging in a single-statesupercharging operation at low flow rates; an operating mode J whereinthe second turbo charging device drives the supercharging in asingle-state supercharging operation at high flow rates; and anoperating mode K wherein the electric motor/generator, controlsrotational speed of the first turbo charging device during a two-statesupercharging operation.
 14. The hybrid system according to claim 13,wherein the plurality of said operating modes comprises: an operatingmode A where the electric motor drives auxiliary loads of the internalcombustion engine (1): an operating mode B where the electric motorstarts, or stops, the internal combustion engine (1): an operating modeC where the electric motor propels the vehicle: and an operating mode Dwhere brake energy from retardation of the vehicle is regenerated toelectrical energy; and wherein the hybrid system operates in a pluralityof different operating modes of A-K.
 15. The hybrid system according toclaim 13; wherein the mode control sequence executes at least one of:engaging or disengaging the first clutch, second clutch and third clutch(18 a, 18 b, 18 c), operating the electric motor (20) in drive mode orgenerate mode, opening or closing a first and a second air by-pass valve(21 a,21 b), and opening or closing a first and a second waste gate (22a, 22 b) based on the selected operating mode (Mode) according to thefollowing: Mode: 18a 18b 18c 20 21a 21b 22a 22b I N/A N/A N/A N/A ClosedOpen N/A Open J N/A N/A N/A N/A Open Closed Open N/A K N/A N/A N/A N/AClosed Closed N/A N/A.


16. The hybrid system according to claim 12, wherein the at least one ofsaid input parameters further comprises: at least one of a firstpressure and a mass flow parameter representative of air intakeoperational state (p1); at least one of a second pressure and a massflow parameter representative of second compressor operational state(p2); at least one of a third pressure and a mass flow parameterrepresentative of first compressor operational state (p3); at least oneof a fourth pressure and a mass flow parameter representative of exhaustgas operational state (p4); at least one of a fifth pressure and a massflow parameter representative of first turbine operational state (p5);and at least one of a sixth pressure and a mass flow parameterrepresentative of second turbine operational state (p6).
 17. The hybridsystem according to claim 1, wherein the electric motor/generator (20)controls rotational speed of the at least one charging device (6; 6 a, 6b).
 18. A hybrid system of an internal combustion engine (1) having asupercharging system, the hybrid system comprising: a charging device(6) with a turbine (7) connected to a compressor (8) via a compressorshaft (9), the compressor having a high speed shaft (30); a planetarygear (25) coupled between the high speed shaft (30) and an electricmotor/generator (20); a clutch (18 a); a power transmission connecting acrank shaft (4) of the combustion engine (1) to the electricmotor/generator, (20) via the clutch (18 a); and an electronic controlsystem (23) configured to operate the hybrid system in a plurality ofdifferent operating modes according to a control sequence based on atleast one of a plurality of input parameters representative ofoperational properties of the hybrid system; wherein the electricmotor/generator (20) comprises a sensor configured to monitor an actualturbo speed without having a turbo speed sensor.
 19. A hybrid system ofan internal combustion engine (1) having a supercharging system, thehybrid system comprising: a charging device (6) with a turbine (7)connected to a compressor (8) via a compressor shaft (9), the compressorhaving a high speed shaft (30); a planetary gear (25) coupled betweenthe high speed shaft (30) and an electric motor/generator (20); a clutch(18 a); a power transmission connecting a crank shaft (4) of thecombustion engine (1) to the electric motor/generator, (20) via theclutch (18 a); and an electronic control system (23) configured tooperate the hybrid system in a plurality of different operating modesaccording to a control sequence based on at least one of a plurality ofinput parameters representative of operational properties of the hybridsystem; wherein the charging device comprises a variable nozzle turbine,the variable nozzle turbine being controlled by determining an errorvalue of a blade speed ratio, BSR_((error)), defined by a difference ina measured blade speed ratio, BSR_((error)), and a desired blade speedratio BSR_((desired)).
 20. A method of operating a hybrid propulsionsystem of a vehicle having an internal combustion engine (1); the hybridpropulsion system comprising: a supercharging system for the internalcombustion engine (1) including an exhaust gas propelled turbosupercharging system, a mechanical supercharging system, and anelectrical supercharging/regenerating system; wherein the exhaust gaspropelled turbo supercharging system includes a turbo charging device(6); the turbo charging device comprising a turbine (7) and a compressor(8), the compressor being arranged on a compressor shaft (9); theexhaust gas propelled turbo supercharging system coupling the turbine(8) to at least one exhaust outlet of the internal combustion engine(1), the electrical supercharging/regenerating system coupling anelectric motor/generator (20) to the compressor shaft via a planetarygear (25), and the mechanical supercharging system coupling a crankshaftof the engine (1) to the electric motor via at least one clutch, whereinthe at least one clutch includes a first clutch (18 a), a second clutch(18 b), and a third clutch (18 c); and wherein the first clutch (18 a)couples a crank shaft of the engine (1) to the electric motor; whereinthe second clutch (18 b) couples the planetary gear/traction device (25)to the electric motor/generator (20); wherein the third clutch (18 c)connects the power transmission to the crank shaft (4) of the combustionengine (1); the method of operating the hybrid system in at least one ofa plurality of different operating modes via an electronic controlsystem (23) comprising at least one of: in an operating mode A, drivingloads of the internal combustion engine (1) with the electricmotor/generator; in an operating mode B, starting, or stopping, theinternal combustion engine (1) with the electric motor/generator; in anoperating mode C, propelling the vehicle with the electricmotor/generator; and in an operating mode D, regenerating electricalenergy from brake energy by retarding of the vehicle.
 21. The methodaccording to claim 20, wherein the plurality of said different operatingmodes comprises: an operating mode E where exhaust gas energy isregenerated to electrical energy; an operating mode F where exhaust gasenergy is regenerated to mechanical energy; an operating mode Gcomprising electrically driven supercharging of the internal combustionengine (1); an operating mode H comprising mechanically drivensupercharging of the internal combustion engine (1).
 22. The methodaccording to claim 20, wherein the exhaust gas turbo charging devicefurther comprises a first turbo charging device (6 a) with a firstturbine (7 a) connected to a first compressor via a first compressorshaft (9 a), and a second turbo charging device comprising a secondturbine (7 b) and a second compressor (8 b), the second compressor beingarranged on a second compressor shaft (9 b).
 23. The method according toclaim 22, wherein the plurality of said different operating modescomprises: in an operating mode I, driving the first turbo chargingdevice in a single-state supercharging operation at low flow rates; inan operating mode J, driving the second turbo charging device in asingle-state supercharging operation at high flow rates; in an operatingmode K, controlling, with the electrical motor/generator, the rotationalspeed of the first turbo charging device during a two-statesupercharging operation.
 24. A control sequence for a hybrid systemincluding an exhaust gas propelled turbo supercharging system, amechanical supercharging system, and an electricalsupercharging/regenerating system, a charging devices and an electricmotor/generator, operatively connected to the charging device; whereinthe hybrid system is arranged to operate in different operating modes;the control sequence being configured for executing of engaging ordisengaging the first clutch, second clutch and third clutch (18 a, 18b, 18 c); wherein the first clutch (18 a) couples a crank shaft of theengine (1) to the electric motor/generator; wherein the second clutch(18 b) couples a planetary gear (25) to the electric motor/generator(20); wherein the third clutch (18 c) connects a power transmission tothe crank shaft (4) of the combustion engine (1); and operating anelectric motor (20) in drive mode or generate mode based on a selectedoperating mode according to the following: Mode: 18a 18b 18c 20 AEngaged Disseng. Disseng. Drive B Engaged Disseng. Engaged Drive CEngaged N/A Engaged Drive D Engaged N/A Engaged. Generate


25. The control sequence for a hybrid system according to claim 24, thecontrol sequence being configured for executing of engaging ordisengaging the first clutch, second clutch and third clutch (18 a, 18b, 18 c), operating the electric motor (20) in drive mode or generatemode, opening or closing an air by-pass valve (21), and opening orclosing a waste gate (22) of the hybrid system based on a selectedoperating mode according to the following: Mode: 18a 18b 18c 20 21 22 EN/A Engaged N/A Generate N/A N/A F Engaged Engaged Engaged Generate N/AN/A G Disseng. Engaged Engaged Drive Closed N/A H Engaged EngagedEngaged N/A Closed N/A.


26. The control sequence for a hybrid system according to claim 24,wherein the exhaust gas turbo charging device further comprises a firstturbo charging device (6 a) with a first turbine (7 a) connected to afirst compressor via a first compressor shaft (9 a), and a second turbocharging device comprising a second turbine (7 b) and a secondcompressor (8 b), the second compressor being arranged on a secondcompressor shaft (9 b).
 27. The control sequence for a hybrid systemaccording to claim 26, the control sequence being configured forexecuting of: engaging or disengaging the first clutch, second clutchand third clutch (18 a, 18 b, 18 c), operating an electric motor (20) indrive mode or generate mode, opening or closing a first and a second airby-pass valve (21 a, 21 b), and opening or closing a first and a secondwaste gate (22 a, 22 b) of the hybrid system based on a selectedoperating mode according to the following: Mode: 18a 18b 18c 20 21a 21b22a 22b I N/A N/A N/A N/A Closed Open N/A Open J N/A N/A N/A N/A OpenClosed Open N/A K N/A N/A N/A N/A Closed Closed N/A N/A.